Retinal drusen are characteristic of macular degeneration and complement activation, but also occur in C3, lupus and IgA nephropathy. This cross-sectional observational study compared drusen counts in different forms of glomerulonephritis. Consecutive individuals with glomerulonephritis attending a general renal or transplant clinic underwent retinal imaging with a non-mydriatic camera. Drusen were counted in deidentified images by trained graders, compared with matched hospital patients, and correlated with clinical features. Eighty-four individuals with glomerulonephritis had a mean drusen count of 10 ± 27 compared with 3 ± 8 in hospital controls (p = 0.007). Fourteen individuals with glomerulonephritis (17%) and 4 hospital controls (4/49, 8%) had increased drusen counts (≥ 10) (p = 0.20). Increased drusen counts ≥ 10 were present in 13 (13/63, 21%) of those with glomerulonephritis and immune deposits [membranous (n = 8), antiglomerular basement membrane nephritis (n = 6), FSGS (n = 49)], and one of the 21 (5%) with glomerulonephritis without immune deposits [ANCA-associated (n = 15), minimal change disease (n = 6)]. In antibody-mediated glomerulonephritis (n = 14), mean drusen counts were 2 ± 3 in individuals with normal kidney function, 16 ± 41 with impaired function and 5 ± 7 with kidney failure . Mean counts were 24 ± 56 in individuals with glomerular IgG deposits and 1 ± 1 in those without (p = 0.76), and 23 ± 60 with complement deposits and 4 ± 8 in those without. Drusen counts were also less in immunosuppressed individuals (p = 0.049). The demonstration of retinal drusen in some forms of glomerulonephritis is consistent with systemic complement activation, and suggests that treatment targeting the complement pathways is worthwhile.
© 2022. The Author(s).